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161.
A technique was developed for synthesis of precursors of nanomaterials from artificial mixtures of aqueous salt solutions, based on flotation extraction followed by reduction of the precursors in direct micelles in view of a surfactant structure. This technique imitates preparation of nanomaterials from hydrometallurgy waste. The resulting materials containing platinum nanoparticles were tested for their ability to catalyze oxidation of carbon monoxide.  相似文献   
162.
We present a quantum-chemical analysis of the relationship between the bond length alteration (BLA) and the static first hyperpolarizability of a series of one-dimensional (1D) chromophores with donor-bridge-acceptor (D-B-A) structures. The calculated results show that the parameter BLA can be considered as an indicator to evaluate the molecular first hyper- polarizability. Along the direction of molecular ground-state dipole moments, the evolutions of BLA can be classified into three categories: the first is a non-monotonic line, which represents most chromophores; the second is monotonic increasing; and the third, contrarily, is monotonic decreasing. On the whole, the first hyperpolarizabilities of these studied chromophores are the monotonic functions of BLA along the direction of dipole moments. Therefore, the first hyperpolarizability of these 1D chromophores can be preliminarily evaluated in terms of the development of BLA without a rigorous computation. In other words, one can roughly estimate the relative magnitude of the first hyperpolarizability according to the optimized geometry.  相似文献   
163.
The process of Gd3+ complexation with 4-dihydroxyborophenylalanine (DHBPA) in aqueous solutions was studied by the contact conductometry, IR, and X-ray photoelectronic spectroscopy methods. The complex formation reactions of Gd3+ with DHBPA were found to occur in steps, depending on the metal: ligand ratio. In the final reaction product, i.e., the chelate complex [Gd(DHBPA)3], each molecule of a ligand occupies two coordination sites.  相似文献   
164.
The interaction of Cd2+ with uracil,2-thiouracil,4-thiouracil and 2,4-dithiouracil have been investigated by the density functional theory(DFT) calculations.For uracil and 2,4-dithiouracil,where the two basic sites are the same,Cd2+ attachment to the heteroatom at position 4 is preferred.However,for the systems where both types of basic centers,a carbonyl and a thiocarbonyl groups,are present,Cd2+ association with sulfur is favorable.The enhanced stability of these enolic and thiol forms comes from Cd2+ interaction with two basic sites simultaneously,which thereby triggers a significant aromatization of the ring.More significantly,the Cd2+ binding energy with uracil and its thio-derivatives is larger than the tautomerization barriers connecting the diketo-like forms with the corresponding enolic-like tautomers.Consequently,when associated with Cd2+,all tautomers are energetically accessible and should be observed in the gas phase.  相似文献   
165.
Prerequisites for the use of photodynamic therapy (PDT) to treatment of atherosclerosis, as well as the development and structure of atherosclerotic vascular lesions in humans are analyzed. The basic requirements for PDT components, specifically photosensitizers (PS), and the radiation source, and the current state of their development are overviewed. Some original results of in vitro studies of the effect of PS on the basis of phthalocyanines and radiation on cells from the atherosclerotic plaques are presented.  相似文献   
166.
Synthesis method is suggested and the size and shape of Pt-Gd particles formed in reduction of metal ions in an aqueous system of direct micelles were determined in relation to the concentration of surfactants and reducing agents: hydrazine hydrate, quercetin, and rutin. The magnetic properties of the nanoparticles obtained were studied.  相似文献   
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